fez
In Weeping Waterfall stage (screenshot of menu), right about here:
there is a secret on the ground near the trees, which looks like several concentric squares when viewed in first-person view:
I cannot for the life of me figure it out, can anyone shed some light on it please?
By turning all of the mini-skulls (hold X) so all of them are facing away from you at the same time, so will the giant skull, revealing the back of it's head.
The square symbols on the bell's four sides are numbers (1, 3, 6, and 10) that represent the amount of times to ring each side. Any order should work. The bell disappears forever, replaced by an anticube.
Best Answer
These are decorative Easter eggs, not a puzzle. Your map node is white most likely because you have another room to find. (Perhaps this one.)
The concentric squares have no bearing on the game or its completion. There are many of them scattered around with different numbers of rings: in Gomez's village (1), atop the broken arch stage (2), atop the bell stage (3), on the 4-cube door's floor (5), atop the waterfall stage (6), on the 16-cube door's temple-under-construction ledge (7), and on the same ledge in the temple warp zone (8), for example.